Chaelbs e



(No Model.)

C. E. SCR'IBNBR.

MICROPHONE.

No. 262,700. Patented Aug. 15, 1882.

=m -{Nimm- E:

:-nnnlIrunl-llln :Z

UNITED STATES PATENT OFFICE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC MANUFACTURING COMPANY, OF SAME PLACE.

MICROPHONE.

SPECIFICATION forming part of Letters Patent No. 262,700, dated August 15, 1882.

Application tiled December 27, 1881.

To all whom it may concern:

Be it known that I, CHARLES E. SCRIBNER, of Chicago, Illinois, have discovered a certain new and useful Improvement in Microphones,

of which the following is a full, clear, concise,

and exact description.

My invention relates to that class of telephonetransmitters in which the electrodes consist ot' a metallic point supported by a spring and a carbon piece at the free end of a loaded yielding support. The contact between the metallic point and the carbon piece may be termed a loose contact;7 since the adjustment is such that the point presses lightly against the carbon piece.

In the Edison carbon transmitter the disks or buttons of carbon which form the electrodes are not in loose contact, but, on the contrary, are held lirmly together by the pressure of the diaphragm. 'Ihe vibrations ofthe diaphragm, however, cannot be increased by the loudest sounds to such an extent as to cause the electrodes to break contact.r The microphone, however, having its electrodes in loose contact, is more especially adapted to the lighter sounds. Very loud sounds, however, directed against the diaphragm of the ordinary microphone cause the electrodes to separate and break contact, so that no intelligible sounds can be heard at the distant receiver. rlhe capacity of the Edison transmitter is not limited by the loudness of the sounds directed against it. In fact, the louder the sound the better (No model.)

stop, preferably of soft rubber, placed on the 4o side ofthe weighted support of the carbon opposite the metallic point, and so adjusted as not to interfere with the vibrations ofthe electrodes, yet so near as to keep the loaded carbon piece from moving far enough away to break contact with the lnctallie point.

In the drawing I have shown the ordinary microphone provided with my improvement.

The diaphragm a is placed upon the frame b, as heretofore. c d is closed through the electrodes ef, in the usual manner. Speaking against the dinphragm varies the resistance ot' the batterycircuit at the point ot' Contact of the metallic point c and the carbon piecef. Loud sounds close to the diaphragm would drive the carbon e piece so far back as to break the circuit. 'lo prevent this I have placed the cushion or stop g, of soft rubber, just back of the loaded piece h, which supports the carbon electrode. The 6o cushion g is supported and adjusted by the screw i. A hole is bored in the `end of the screw to receive the soft-rubber cushion. The stop should be ad justcd so as to touch or nearly touch the piece h.

I have used hard rubber with good results, instead ot' the soft rubber. I may omit the' rubber piece g and use the screw i as the stop.

I claim- The combination, in a microphone, ofthe 7o electrodes suspended in loose contact with an adjustable stop, whereby the separation of the electrodes is prevented when loud sounds are directed against the diaphragm.

CHARLES E. SCRIBNER.

Witnesses:

GEORGE P. BARTON, WILLIAM S. GRANGER.

rIhe battery-circuit of lines 5o 

